For example, drawers of a wagon are generally supported in a drawer storage portion as being a box body through a suspension rail mechanism or the like. Especially, since a great deal of goods is stored in a deep drawer locating at the lowest, a big load is applied to the drawer on a full-time basis.
In consideration of the above, a supporting unit to support this kind of a drawer adopts an arrangement as shown in a patent document 1 wherein at least a rear end side of a drawer is supported in a manner movable along back and forth in a drawer storage portion as being a box body through a suspension rail mechanism and a front end side thereof is supported in a manner movable along back and forth by a floor through an auxiliary wheel so as to prevent a front portion of the drawer from hanging down.    Patent Document 1: Patent Laid-Open No. 2001-186946
The auxiliary wheel is axially mounted on a bottom face at a center along a width of the front end side of the drawer through a bracket and moves at the same speed as that of the drawer. Since this kind of a conventional auxiliary wheel has an arrangement wherein an area that contacts with a floor is small with a relatively narrow width, friction between the auxiliary wheel and the floor increases, thereby requiring an excessive operational force especially for cases wherein the floor is soft or a load capacity of a drawer is big.